Scientists came up with an explanation
for why (Americas) Indians and Asians both had mostly straight dark hair, a
land bridge. A few hundred years before they came up with the land bridge, they didn't even know that the New World existed, and they already have an explanation for
something like that. At one time, humans were all one people from the same place (before the continents became different continents), in that sense, (Americas) Indians and Asians come from the same place. Otherwise, there's not much connection.
Sure, at one time the land might have
stretched out between two different lands like
dough before the sea washed it away, but there's also a lot of other things that could have happened. The land bridge is just one attempt to explain it, which is why science is meant to be
taken with a grain of salt (even science related to the coronavirus).